如何有條件地刪除where子句中的條件？

Question

SELECT * FROM someTable WHERE someField = 'A' 
and (EndTime > @someTime OR EndTime IS NULL) 

上面是原始查詢。現在我有一個新的條件，看看是否帶走EndTime IS NULL。

SET @Throw = 1; 

IF @Throw = 1 
BEGIN 
    SELECT * FROM someTable WHERE someField = 'A' 
    and (EndTime > @someTime) 
END 
ELSE IF @Throw = 0 
BEGIN 
    SELECT * FROM someTable WHERE someField = 'A' 
    and (EndTime > @someTime OR EndTime IS NULL) 
END 

我想知道如果這可以實現1查詢本身或它必須在2查詢？

Answer 1

SELECT * FROM someTable WHERE someField = 'A' 
and (EndTime > @someTime OR (@Throw = 0 AND EndTime IS NULL)) 

Answer 2

SELECT * FROM someTable WHERE someField = 'A' 
    and (EndTime > @someTime AND @Throw = 1) OR ((EndTime > @someTime OR EndTime is NULL) AND @Throw = 0)